An instance simulating the VERY end of 1.0 would be a neat idea. Spawning into an old Mor Dhona area, fighting wave after wave of Garleans.

Unfortunately, that was never meant to have a win state, it just "ended" when they shut off the servers (i.e. when Dalamud struck), so I'm not really sure how that part would work... Stay alive for some duration, I suppose?